静态方法返回内部类 [英] Static method returning inner class

问题描述

我真的不明白为什么下面的getMyClass2方法不能是静态的，为什么它不是有效的Java代码?

I really don't understand why the getMyClass2 method below cannot be static, why isn't it valid Java code?

public class MyClass
{
    private class MyClass2
    {
        public String s1 = "";
        public String s2 = "";
    }

    private MyClass2 myClass2;

    private static MyClass2 getMyClass2()
    {
        MyClass2 myClass2 = new MyClass2();
        return myClass2;
    }

    public MyClass()
    {
        myClass2 = getMyClass2();
    }
}

推荐答案

您必须说内部类是静态的，因为非静态绑定到实例，所以它不能从静态方法中返回

You have to say that the inner class is static because non-static is bound to the instance so it cannot be returned from static method

public class MyClass
{
    private static class MyClass2
    {
        public String s1 = "";
        public String s2 = "";
    }

    private MyClass2 myClass2;

    private static MyClass2 getMyClass2()
    {
        MyClass2 myClass2 = new MyClass2();
        return myClass2;
    }

    public MyClass()
    {
        myClass2 = getMyClass2();
    }
}

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